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Abstract:

A key assembly comprises a base plate and two keys. The base plate has an
opening defined therein and two opposite first inner walls formed in the
opening, each first inner wall has two mating space defined therein and
spaced from each other. Each key has two opposite sidewalls, each
sidewall has a shaft protruding therefrom and corresponding to the mating
spaces, the shafts is rotatably received in the mating spaces.

Claims:

1. A key assembly comprising:a base plate, the base plate defining an
opening having two opposite first inner walls, each first inner wall
having two mating spaces defined therein and spaced from each other;
andtwo keys received in the opening, each key having two opposite
sidewalls, each sidewall having a shaft protruding therefrom and
corresponding to the mating spaces, the shafts rotatably received in the
mating spaces.

2. The key assembly of claim 1, wherein each mating space includes a
aperture defined in the center of the first inner wall, the shafts are
rotatably accommodated in the aperture.

3. The key assembly of claim 2, wherein each mating space further includes
a guiding groove defined in an inner surface of the peripheral wall
communicating with corresponding aperture, the guiding grooves are
configured to guide the shafts into the apertures.

4. The key assembly of claim 3 wherein the width of the guiding grooves
are smaller than the diameter of the shafts.

5. The key assembly of claim 4 wherein each side of each guiding groove
has a notch defined therein, so four expanding portions are defined
between the notches and the guiding grooves, when the shafts move in the
guiding grooves, the expanding portions are bent toward the notches to
enlarge the width of the guiding grooves.

6. The key assembly of claim 1 wherein each key has a first end and a
second end located opposite to the first end, the shafts is located
adjacent to the first end, the second end has a stopping portion
protruding outwardly, the base plate has a trough defined therein and
corresponding to the stopping portion, the stopping portion is latched in
the trough to prevent the second end from detaching from the opening.

7. The key assembly of claim 1 wherein the base plate includes a
peripheral wall and a bottom wall connecting with the peripheral wall,
the opening is defined in the peripheral wall.

8. The key assembly of claim 1 wherein the shafts of each key are coaxial.

9. A portable electronic device, comprising:a circuit board having
switches mounted thereon; and a key assembly including:a base plate, the
base plate defining an opening having two opposite first inner walls,
each first inner wall having two mating spaces defined therein and spaced
from each other; andtwo keys used to control the switches of the circuit
board, each key having two opposite sidewalls, each sidewall having a
shaft protruding therefrom and corresponding to the mating spaces, the
shafts rotatably received in the mating spaces.

10. The portable electronic device of claim 9, wherein each mating space
includes a aperture defined in the center of the first inner wall, the
shafts are rotatably accommodated in the aperture.

11. The portable electronic device of claim 10, wherein each mating space
further includes a guiding groove defined in an inner surface of the
peripheral wall communicating with corresponding aperture, the guiding
grooves are configured to guide the shafts into the apertures.

12. The portable electronic device of claim 11 wherein the width of the
guiding grooves are smaller than the diameter of the shafts.

13. The portable electronic device of claim 12 wherein each side of each
guiding groove has a notch defined therein, so four expanding portions
are defined between the notches and the guiding grooves, when the shafts
move in the guiding grooves, the expanding portions are bent toward the
notches to enlarge the width of the guiding grooves.

14. The portable electronic device of claim 9 wherein each key has a first
end and a second end located opposite to the first end, the shafts is
located adjacent to the first end, the second end has a stopping portion
protruding outwardly, the base plate has a trough defined therein and
corresponding to the stopping portion, the stopping portion is latched in
the trough to prevent the second end from detaching from the opening.

15. The key assembly of claim 9 wherein the base plate includes a
peripheral wall and a bottom wall connecting with the peripheral wall,
the opening is defined in the peripheral wall.

16. The key assembly of claim 9 wherein the shafts of each key are
coaxial.

Description:

[0001]This application is related to co-pending U.S. patent application
(Attorney Docket No. US22371, entitled "KEY ASSEMBLY AND PORTABLE
ELECTRONIC DEVICE USING THE SAME", by Mu-Wen Yang et al. Such application
has the same assignee as the present application and has been
concurrently filed herewith. The above-identified application is
incorporated herein by reference.

[0005]With the development of smaller and lighter electronic devices for
portable use, key assemblies have become more compact with keys more
tightly spaced. Unfortunately, users of these portable electronic
sometimes experience difficulty in pressing keys that are placed so close
together; users may easily press more than one key at a time or press a
wrong key. This drawback exists for users of cellular telephones and
other portable electronic devices with key assemblies.

[0006]Thus, there is room for improvement within the art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]Many aspects of the embodiments can be better understood with
references to the following drawings. The components in the drawings are
not necessarily drawn to scale, the emphasis instead being placed upon
clearly illustrating the principles of the exemplary key assembly and
portable electronic device using key assembly. Moreover, in the drawings
like reference numerals designate corresponding parts throughout the
several views. Wherever possible, the same reference numbers are used
throughout the drawings to refer to the same or like elements of an
embodiment.

[0008]FIG. 1 is an exploded, isometric view of one embodiment of a key
assembly used in a portable electronic device, the portable electronic
device including the key assembly, a housing, and a circuit board.

[0009]FIG. 2 is similar to FIG. 1, but showing the portable electronic
device in another aspect.

[0010]FIG. 3 is a cutaway, assembled view of the portable electronic
device shown in FIG. 1.

[0011]FIG. 4 is a cross-sectional view of the portable electronic device
shown in FIG. 3.

DETAILED DESCRIPTION

[0012]Referring to FIGS. 1 to 3, an exemplary embodiment of a key assembly
10 can be used in a portable electronic device 100, such as a cellular
phone or any electronic device where a key is desirable. The portable
electronic device 100 includes a circuit board 30 and a key assembly 10
configured to control the circuit board 30. The circuit board 30 has two
spaced apart switches 32 mounted thereon. The key assembly 10 is
configured so that pressing of the first switches 32 can control the
circuit board 30.

[0013]The key assembly 10 includes a base plate 20 and keys 12
corresponding to the switches 32. The base plate 20 may be a portion of a
housing of the portable electronic device 100 or may be a separate
element mounted to a housing of the portable electronic device 100. In
this embodiment, the base plate 10 is a portion of a housing of the
portable electronic device 100. Each key 12 may have any shape. Each key
12 has a first end 121 located adjacent to another key 12, a second end
122 opposite to the first end 121, a contacting surface 123 facing the
circuit board 30, an operating surface 124 opposite to the contacting
surface 123 and two opposite sidewalls 125 connecting the contacting
surface 123 to the operating surface 124.

[0014]Each contacting surface 123 has a contacting portion 126 protruding
from the center thereof. The contacting portions 126 are configured for
triggering the switches 32, correspondingly. The contacting portions 126
may be constructed from injection-molded thermoplastic elastomer and
configured to produce a point contact sensation in a user's fingertip to
provide tactile feedback when a user presses the key 12. The operating
surface 124 may have an indicia 127 defined thereon, to indicate the
function of the first key 12. The indicia 127 may be, e.g., "+" or "-",
to indicate the functions of the keys 12 are increasing volume or
decreasing volume, correspondingly.

[0015]Each sidewall 125 has a shaft 128 protruding therefrom adjacent to
the first end 121, and the shafts 128 are coaxial. Each key 12 has a
stopping section 129 protruding from the second end 122 thereof. The
stopping sections 129 are configured for preventing the keys 12 from
detaching from the base plate 20.

[0016]The base plate 20 includes a peripheral wall 22 and a bottom wall 24
substantially perpendicularly connected to the peripheral wall 22. The
peripheral wall 22 has an opening 222 defined therein corresponding to
the keys 12. The opening 222 is sized and configured to be engaged with
the key 12. The base plate 20 includes two opposite first inner walls
2221 and two opposite second inner walls 2227 bounding the opening 222.

[0017]The first inner walls 2221 are parallel to the bottom wall 24, and
each first inner wall 2221 has two mating spaces 2222 defined therein and
spaced from each other. Each mating space 2222 includes a aperture 2223
defined in a center of the first inner wall 2221 and a guiding groove
2224 defined in an inner surface of the peripheral wall 22. The
cross-section of the aperture 2223 is the same size and shape as the
shaft 128 and is configured to accommodate the shaft 128 therein. The
cross-section of the guiding groove 2224 is rectangular and communicates
with the aperture 2223. The width of the guiding groove 2224 is smaller
than the diameter of the shaft 128. The guiding groove 2224 is configured
to guide the shaft 128 into the aperture 2223.

[0018]Each first inner wall defines a notch 2225 adjacent two opposite
sides of each guiding groove 2224, thus forming two expanding portions
2226 between each notch 2225 and nearest guiding groove 2224. When the
shafts 128 move into the guiding grooves 2224, the expanding portions
2226 are bent toward the notches 2225 to enlarge the width of the guiding
grooves 2224 such that the shafts 128 easily enter into the apertures
2223. Each second inner wall 2227 has a trough 224 defined therein, and
the troughs 224 communicate with an inner surface of the peripheral wall
22. The troughs 224 are configured for accommodating the stopping
sections 129 of the keys 12.

[0019]Referring to FIGS. 3 and 4, to assemble the portable electronic
device, first, the shafts 128 are aligned with the guiding grooves 2224,
and the stopping sections 129 are aligned with the troughs 224. Second,
the keys 12 are pressed such that the shafts 128 are moved in the guiding
grooves 2224 until the shafts 128 are accommodated in the aperture 2223,
correspondingly. At this time, the stopping sections 129 are accommodated
in the troughs 224. Then, the circuit board 30 is attached to the bottom
wall 24 with the switches 32 correspondingly resisting against the
contacting portions 126, thus yielding an assembled portable electronic
device 100.

[0020]Referring further to FIG. 4, to use the key assembly 10, first, the
second ends 122 of the keys 12 are pressed toward the switches of the
circuit board 30, so the keys 12 are rotated about the shafts 128 to
enter into the base plate 20 until the contacting portions 126 trigger
the switches 32 to control the circuit board 30. At this time, the
contacting portions 126 and the switches 32 are compressed to accumulate
elastic force, and the stopping sections 129 are out of the troughs 224.
Once the switches 32 are triggered, the keys 12 are released so that the
keys 12 rebounded until the stopping sections 129 are accommodated in the
troughs 224 again.

[0021]Because the second ends 122 of the keys 12 are pressed when using
the keys 12, and each second end 122 faces away from another key 12, a
user's fingertip touches only one key 12 at a time, thus removing the
possibility of hitting two keys at once.

[0022]It is to be understood, however, that even though numerous
characteristics and advantages of the exemplary disclosure have been set
forth in the foregoing description, together with details of the
structure and function of the disclosure, the disclosure is illustrative
only, and changes may be made in detail, especially in matters of shape,
size, and arrangement of parts within the principles of the disclosure to
the full extent indicated by the broad general meaning of the terms in
which the appended claims are expressed.